WO2019069568A1

WO2019069568A1 - Sound output device, earphone, hearing aid, and mobile terminal device

Info

Publication number: WO2019069568A1
Application number: PCT/JP2018/030615
Authority: WO
Inventors: 和之小須田; 雄史松尾; 勇一小林; 泰博牧野
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2017-10-04
Filing date: 2018-08-20
Publication date: 2019-04-11
Also published as: JPWO2019069568A1; US20200366996A1; EP3694221A4; EP3694221A1; CN111052761A

Abstract

A sound output device (1) comprises: a speaker (10) that has a vibration board (11); a behind-the-speaker space (110) that is located behind the speaker (10) on the opposite side from the vibration board (11); and a cable (105) that is electrically connected to the speaker (10) and extends to the outside from inside the behind-the-speaker space (110). The speaker (10) comprises: a behind-the-vibration-board space (31) that is located behind the vibration board (11) on the opposite side from a sound radiation direction; and a sound hole (30) having a first opening (30a) that opens to the behind-the-vibration-board space (31) and a second opening (30b) that opens to the behind-the-speaker space (110). When viewed in the direction from the first opening (30a) to the second opening (30b), the cable (105) inside the behind-the-speaker space (110) is disposed outside a region occupied by the sound hole (30).

Description

Sound output device, earphone, hearing aid and portable terminal device

The present disclosure relates to an acoustic output device, an earphone, a hearing aid, and a portable terminal device.

2. Description of the Related Art In recent years, with the spread of portable terminal devices such as smart phones, the demand for acoustic output devices mounted on portable terminal devices or earphones is increasing. For example, Patent Document 1 discloses an earphone in which a sound hole penetrating the speaker is formed in the speaker. The sound holes communicate the space on the back side of the diaphragm of the speaker with the space on the back side of the speaker.

Patent No. 6136016 gazette

The air in the sound hole vibrates with the diaphragm to generate a flow of reciprocating air. In the earphone disclosed in Patent Document 1, there is a possibility that the sound pressure frequency characteristic of the earphone may be unintended due to interference between an obstacle such as a cord disposed at the outlet of the sound hole and the air flow. .

The present disclosure provides an acoustic output device, an earphone, a hearing aid, and a portable terminal device that improve sound pressure frequency characteristics.

A sound output device according to one non-limiting and exemplary aspect of the present disclosure includes: a speaker having a diaphragm; a speaker back space located at a back of the speaker opposite to the diaphragm; And a cable connected to the speaker back space and extending from the inside to the outside of the speaker back space, wherein the speaker is connected to a diaphragm back space located at the back of the diaphragm opposite to a sound radiation direction; The cable in the speaker back space, when viewed from the first opening toward the second opening, includes a hole having a first opening that opens and a second opening that opens to the speaker back space. It is located outside the area of the hole.

An earphone according to a non-limiting and exemplary aspect of the present disclosure includes the above-mentioned sound output device.

A hearing aid according to one non-limiting and exemplary aspect of the present disclosure comprises the above-mentioned sound output device.

A portable terminal device according to a non-limiting and exemplary aspect of the present disclosure includes the above-mentioned sound output device.

According to the technology of the present disclosure, it is possible to improve sound pressure frequency characteristics.

FIG. 1 is a schematic perspective view of an example of an earphone provided with the sound output device according to the embodiment. FIG. 2 is a schematic exploded perspective view of the earphone of FIG. FIG. 3 is a schematic cross-sectional side view looking in the direction III, the cross section of cutting the earphone of FIG. 1 through the cable and from the earpiece to the back cover. FIG. 4 is a schematic perspective sectional view of the earphone of FIG. 1 with the same cross section as that of FIG. 3 cut away. FIG. 5 is a schematic perspective sectional view in which a cross section perpendicular to the cross section in FIG. 3 is cut away in the earphone of FIG. 1, and the cross section is viewed in the direction V. FIG. 6 is a schematic cross-sectional view showing an example of the cross-sectional configuration of the cable. FIG. 7 is a schematic cross-sectional side view showing the speaker of FIG. 3 in an enlarged manner. FIG. 8 is a view showing the earphone of FIG. 5 upside down. FIG. 9 is a diagram showing sound pressure frequency characteristics in the example and the comparative example. FIG. 10 is a schematic view showing an example of a hearing aid to which the sound output device according to the embodiment is applied. FIG. 11 is a schematic view showing an example of a portable terminal device to which the sound output device according to the embodiment is applied.

The present inventors examined the structure which has a sound hole in a speaker like the earphone of patent document 1 mentioned by "the background art" in examining a small and highly efficient sound output device. Generally, the air on the back side of the diaphragm in the speaker vibrates with the diaphragm and is subjected to compression or expansion. Air subjected to compression or expansion may affect the operation of the diaphragm. However, as in the earphone described in Patent Document 1, the provision of the sound holes increases the volume of the space on the back side of the diaphragm and reduces the pressure change of the space, so the above-mentioned influence is relatively low. It is suppressed.

The present inventors have found a problem that a relationship between a desired sound pressure and a frequency of a diaphragm, that is, a sound pressure frequency characteristic can not be obtained in the process of examining the configuration of the earphone as described in Patent Document 1 . As a result of examining this factor, the present inventors have found that an obstacle such as a cord disposed close to the exit of the sound hole opposite to the diaphragm can affect the sound pressure frequency characteristic. The The air in the sound hole reciprocates along with the vibration of the diaphragm, whereby part of the air moves in and out of the sound hole. However, if an obstacle is present in the vicinity of the outlet of the sound hole, the air entering and exiting the sound hole interferes with the obstacle and the pressure of the air in the sound hole is affected. Since this influence changes in various ways according to the frequency of the diaphragm, it is difficult to realize a desired sound pressure frequency characteristic.

The outlet of the sound hole may be covered with a porous damping member in order to suppress excessive vibration of the air on the back side of the diaphragm. In such a configuration, as air in the sound hole vibrates, a jet flow passing through the braking member is generated. Even if the jet interferes with the obstacle, the pressure of the air in the sound hole is affected, and the desired sound pressure frequency characteristic can not be obtained. Therefore, the present inventors have devised the following technology in order to improve the sound pressure frequency characteristics.

A sound output device according to an aspect of the present disclosure includes: a speaker having a diaphragm; a speaker back space located at a back of the speaker opposite to the diaphragm; and a speaker back space electrically connected to the speaker And a cable extending from the inside to the outside of the speaker, wherein the speaker comprises: a diaphragm back space located at the back of the diaphragm opposite to a sound radiation direction; a first opening opened to the diaphragm back space; And a hole having a second opening that opens into the speaker back space, wherein the cable in the speaker back space is disposed outside the area of the hole when viewed from the first opening toward the second opening It is done.

According to the above aspect, the vibration in the diaphragm causes the air in the hole to vibrate and repeat the outflow and inflow to the speaker back space. Since the cable in the speaker back space is disposed outside the area of the hole, air flowing into the speaker back space is prevented from interfering with the cable. Thereby, since the pressure change of the air in the hole due to the interference between the outflow air and the cable is suppressed, it is possible to reduce the influence of the vibration of the diaphragm from the pressure change. Thus, the sound output device enables improvement in sound pressure frequency characteristics.

The sound output device according to an aspect of the present disclosure further includes a wall that forms the speaker back space between the speaker and the speaker, and the wall communicates the speaker back space with the second opening and the second opening. The cable may be disposed outside the area of the wall hole when viewed from the first opening toward the second opening.

According to the above aspect, the air flowing out of the hole into the speaker back space smoothly flows out of the speaker back space through the wall hole. Therefore, the pressure change of the air in the hole due to the interference of the air flowing out to the speaker back space is suppressed.

In the sound output device according to one aspect of the present disclosure, when viewed from the first opening toward the second opening, one region of the hole and the wall hole is the other of the hole and the wall hole. It may be included in the area.

According to the above aspect, air can efficiently flow from the hole to the wall hole. Therefore, the air flowing out from the hole to the back space of the speaker is prevented from being interfered.

In the sound output device according to one aspect of the present disclosure, the cable may be arranged to extend from the speaker in a direction along the hole in the speaker back space.

According to the above aspect, the cable in the speaker back space can be easily disposed outside the area of the hole. In addition, since the area occupied by the cable in the speaker back space can be kept low, the volume of air in the speaker back space can be increased. Thereby, since the pressure fluctuation of the speaker back space at the time of the air vibration in the hole is suppressed to a low level, the influence of the air in the speaker back space on the air in the hole is suppressed.

In the sound output device according to one aspect of the present disclosure, the speaker includes a magnet surrounding the hole, and a first member surrounding the hole and magnetically coupled to a first magnetic pole of the magnet. The voice coil includes a second member surrounding the hole and magnetically coupled to the second magnetic pole of the magnet, and a voice coil surrounding the hole and connected to the diaphragm. The magnetic gap may be disposed between a first facing portion of the first member and a second facing portion of the second member facing the first facing portion.

According to the above aspect, the hole is formed to penetrate the first member, the second member and the magnet. Therefore, since the holes, the first member, the second member, the magnet, and the voice coil can be efficiently arranged, the speaker can be miniaturized.

In the sound output device according to one aspect of the present disclosure, the speaker may further include a magnetic fluid disposed between at least one of the first facing portion and the second facing portion and the voice coil.

According to the above aspect, the magnetic fluid stably holds the vibrating voice coil with respect to at least one of the first member and the second member. Therefore, the sound quality of the speaker can be improved.

In the sound output device according to one aspect of the present disclosure, the speaker may further include a circuit board surrounding the hole and electrically connected to the voice coil and the cable.

According to the above aspect, the hole is formed to penetrate the circuit board. Therefore, since the efficient arrangement of the circuit board in the speaker is possible, the speaker can be miniaturized.

In addition, an earphone according to one aspect of the present disclosure includes the above-described sound output device. According to the above aspect, the same effect as the sound output device according to one aspect of the present disclosure can be obtained.

Moreover, a hearing aid according to an aspect of the present disclosure includes the above-described sound output device. According to the above aspect, the same effect as the sound output device according to one aspect of the present disclosure can be obtained.

Furthermore, a portable terminal device according to an aspect of the present disclosure includes the above-described sound output device. According to the above aspect, the same effect as the sound output device according to one aspect of the present disclosure can be obtained.

Embodiment
Hereinafter, a sound output device and the like according to an embodiment of the present disclosure will be specifically described with reference to the drawings. Note that all the embodiments described below show general or specific examples. Numerical values, shapes, components, arrangement positions and connection forms of components, steps (steps), order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present disclosure. Further, among the components in the following embodiments, components not described in the independent claim indicating the highest concept are described as arbitrary components. Further, in the following description of the embodiments, expressions accompanied by “abbreviation” such as substantially parallel or substantially orthogonal may be used. For example, “substantially parallel” means not only completely parallel but also substantially parallel, that is, including, for example, a difference of several% or so. The same applies to expressions accompanied by other "abbreviations". Further, each drawing is a schematic view, and is not necessarily illustrated exactly. Further, in the drawings, substantially the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

Hereinafter, the sound output device 1 according to the embodiment will be described. In the present embodiment, an example in which the sound output device 1 is mounted on an earphone will be described. For example, FIG. 1 shows a schematic perspective view of an example of an earphone provided with the sound output device 1 according to the embodiment. FIG. 2 shows a schematic exploded perspective view of the earphone 100 of FIG. FIG. 3 shows a schematic cross-sectional side view looking in the direction III of a cross section through the cable 105 and cutting the earphone 100 of FIG. 1 from the earpiece 101 to the back cover 104. As shown in FIGS. 1 to 3, the earphone 100 includes an earpiece 101, a port 102, a speaker 10, a box 103, a back cover 104, and a cable 105.

The port 102 integrally has a bottomed cylindrical main body 102a and a sound conduit 102b extending from a bottom wall 102aa of the main body 102a. The earpiece 101 is a member to be inserted into the hole of the ear of the wearer of the earphone 100. Earpiece 101 is assembled to sound conduit 102 b of port 102. The earpiece 101 has a through hole 101a that opens in the outer ear of the wearer, and the through hole 101a communicates with the sound conduit 102b. The outer surface of the earpiece 101 may be constituted by an exposed surface of the constituent material of the earpiece 101, and may be covered with an elastic buffer material such as rubber or sponge. Note that the earpiece 101 itself may be formed of a buffer material having elasticity.

The bottomed cylindrical box 103 is assembled with the main body 102 a of the port 102, and the box 103 and the main body 102 a form an accommodating space 108 therein. The housing space 108 is located between the bottom wall 103a of the box 103 and the bottom wall 102aa of the main body 102a, and communicates with the sound conduit 102b. The speaker 10 is disposed in the housing space 108 and emits sound toward the sound conduit 102 b. That is, the speaker 10 is disposed with the diaphragm 11 directed to the sound conduit 102b. The sound generated by the diaphragm 11 of the speaker 10 passes through the sound conduit 102 b and the through hole 101 a of the earpiece 101 to reach the wearer's ear.

The bottomed cylindrical back cover 104 is assembled with the box 103 opposite the port 102. The back cover 104 covers the bottom wall 103 a of the box 103. The box 103 and the back cover 104 form a cable space 109 inside. The cable space 109 is located between the bottom wall 103 a of the box 103 and the bottom wall of the back cover 104 and communicates with the housing space 108. The back cover 104 is formed with an insertion hole 104 a through which the cable 105 passes. Although two insertion holes 104 a are formed in the example of FIGS. 2 and 3, they may be one. The cable 105 electrically connects the device to which the earphone 100 is connected and the speaker 10. That is, the cable 105 is electrically connected to the speaker 10. The cable 105 extends from the outside of the box 103 and the back cover 104 through the insertion hole 104 a into the cable space 109, and further extends into the housing space 108 and is connected to the speaker 10. In other words, the cable 105 extends from the inside to the outside of the speaker back space 110, which will be described later, formed in the housing space 108.

The earpiece 101, the port 102, the box 103 and the back cover 104 constitute a housing (also referred to as a "housing") of the earphone. The earpiece 101, the port 102, the box 103 and the back cover 104 are arranged in this order and assembled to one another. In the present embodiment, the earpiece 101, the port 102, the box 103 and the back cover 104 are coaxially arranged on the axis C. In addition, the shape and arrangement of the earpiece 101, the port 102, the box 103 and the back cover 104 are not limited to the above, and any shape and arrangement may be employed.

The housing space 108 is surrounded by a disk-shaped bottom wall 102 aa and a cylindrical side wall 102 ab of the main body 102 a of the port 102 and a disk-shaped bottom wall 103 a and a cylindrical side wall 103 b of the box 103. The speaker 10 is disposed at a distance from the bottom wall 103 a in the axis C direction. In the present embodiment, the axis C and the bottom wall 103 a are in a substantially perpendicular relationship, but the invention is not limited thereto. Thereby, the speaker back space 110 is formed between the speaker 10 and the bottom wall 103a. In other words, the bottom wall 103 a forms a speaker back space 110 with the speaker 10. Such a speaker back space 110 is located at the back of the speaker 10 opposite to the diaphragm 11. The speaker back space 110 is surrounded by the speaker 10, the bottom wall 103a, and the side wall 103b. Here, the speaker 10, the speaker back space 110 and the cable 105 constitute the sound output device 1. Bottom wall 103a is an example of a wall.

The speaker 10 has a diaphragm back space 31 at the back of the diaphragm 11 opposite to the sound radiation direction. Furthermore, the speaker 10 has a sound hole 30. The sound hole 30 extends through the speaker 10 and communicates the diaphragm back space 31 and the speaker back space 110. The sound hole 30 has a first opening 30 a opening to the diaphragm back space 31 and a second opening 30 b opening to the speaker back space 110. The sound hole 30 is not limited to this, and in the present embodiment, the sound hole 30 is a straight linear hole along the axis C. Specifically, the axial center of the sound hole 30 is the axis C, but is not limited thereto. In addition, the sound hole 30 may be inclined with respect to the axis C, for example, and may include a curved linear shape. Here, the sound hole 30 is an example of a hole.

Moreover, the speaker 10 has the 1st damping | braking part 19 which covers the 2nd opening 30b. The first braking portion 19 enables the air in the sound hole 30 to flow out to the speaker back space 110 and the air in the speaker back space 110 to flow into the sound hole 30 while limiting them. Such first braking portion 19 suppresses excessive vibration of air in the sound hole 30 and prevents foreign matter from entering the sound hole 30. The first braking portion 19 is made of a porous material, and examples of the constituent material of the first braking portion 19 are an acoustic damping cloth, a material having a plurality of through holes, a mesh-like non-woven fabric, a woven fabric and the like.

As shown in FIGS. 3 to 5, when viewed from the first opening 30 a to the second opening 30 b, the cable 105 in the speaker back space 110 is an area occupied by the sound hole 30, that is, an area of the sound hole 30. It is arranged to be located outside. 4 is a schematic perspective sectional view of the earphone 100 of FIG. 1 with the same section as that of FIG. 3 cut away. FIG. 5 is a schematic perspective sectional view in which a cross section perpendicular to the cross section in FIG. 3 is cut away in the earphone 100 of FIG. 1, and the cross section is viewed in the direction V.

In the present embodiment, as shown in FIG. 6, the cable 105 includes two conductive core wires 105a and an electrically insulating sheath 105b covering the two core wires 105a. That the cable 105 is located outside the area of the sound hole 30 means that the two core wires 105 a and the outer skin 105 b are located outside the area of the sound hole 30. For example, if the cable 105 has one or more core wires 105a and a shell 105b, all the core wires 105a and the shell 105b are located outside the area of the sound hole 30. If the cable 105 does not have the sheath 105 b, all the core wires 105 a are located outside the area of the sound hole 30. 6 is a schematic cross-sectional view showing an example of the cross-sectional configuration of the cable 105. As shown in FIG.

Further, in the present embodiment, the area of the sound hole 30 is also the area of the sound hole 30 when the sound hole 30 is viewed in the direction of the axis C. When viewed from the first opening 30a to the second opening 30b, if the sound hole 30 has a linear shape, the sound hole 30 is viewed along a straight line connecting the center of the first opening 30a and the center of the second opening 30b. It may be When the linear shape of the sound hole 30 includes a bend such as a curve, looking from the first opening 30 a toward the second opening 30 b is to look in a linear tangential direction of the sound hole 30 at the second opening 30 b It is also good. Further, the area of the sound hole 30 is an area of the minimum cross section of the sound hole 30 when viewed from the first opening 30a toward the second opening 30b, an area of the maximum cross section of the sound hole 30, or an area of the second opening 30b. It may be either. For example, if the sound hole 30 is shaped to expand or contract from the first opening 30a toward the second opening 30b, the area of the sound hole 30 may be the area of the second opening 30b.

Further, as shown in FIGS. 2 to 5, in the bottom wall 103a of the box 103, a wall portion hole 103aa penetrating the bottom wall 103a is formed. The wall hole 103aa communicates the speaker back space 110 with the cable space 109. That is, the wall holes 103aa communicate the speaker back space 110 to the outside. The wall hole 103 aa is opened opposite to the second opening 30 b of the sound hole 30. Further, the bottom wall 103a is provided with a second braking portion 106 which covers the opening 103ab of the wall hole 103aa. The second braking portion 106 has the same function as the first braking portion 19, suppresses excessive vibration of air in the speaker back space 110, and prevents foreign matter from entering the speaker back space 110. The constituent material of the second braking portion 106 may be the same material as the material described above for the first braking portion 19.

In addition, the third braking portion 107 covering the opening of the sound conduit 102b is also provided in the sound conduit 102b of the port 102. The third braking portion 107 has the same function as the first braking portion 19, suppresses excessive vibration of air in the sound conduit 102b, and prevents foreign matter from entering the sound conduit 102b. The constituent material of the third braking portion 107 may be the same material as the material described above for the first braking portion 19.

Further, in the present embodiment, when viewed from the first opening 30a to the second opening 30b, the cable 105 in the speaker back space 110 is disposed outside the region of the wall hole 103aa. There is. The area of the wall hole 103aa is the area of the minimum cross section of the wall hole 103aa when viewed from the first opening 30a toward the second opening 30b, the area of the maximum cross section of the wall hole 103aa, or the speaker back space 110 It may be any of the area of the opening 103ab of the wall hole 103aa. In the case where the wall hole 103aa has a cross section significantly larger than the sound hole 30, the cable 105 may be located in the region of the wall hole 103aa.

As described above, in the present embodiment, when viewed from the first opening 30a to the second opening 30b, the cable 105 in the speaker back space 110 is located outside the area of the sound hole 30, and the wall It is located in the outer side of the area | region of partial hole 103aa. Preferably, the cable 105 in the speaker back space 110 is located at least outside the area of the sound hole 30. The cable 105 in the speaker back space 110 may be located outside the area connecting the second opening 30 b of the sound hole 30 and the opening 103 ab of the wall hole 103 aa.

Further, when viewed from the first opening 30a toward the second opening 30b, one region of the sound hole 30 and the wall hole 103aa is included in the other region of the sound hole 30 and the wall hole 103aa. In the present embodiment, since the cross section of the sound hole 30 is larger than the cross section of the wall hole 103 aa, the region of the wall hole 103 aa is included in the region of the sound hole 30. Further, the sound hole 30 and the wall hole 103aa are coaxially arranged. However, for example, when the cross section of the wall hole 103aa is larger than the cross section of the sound hole 30, the region of the sound hole 30 may be included in the region of the wall hole 103aa. The relative positional relationship between the sound hole 30 and the wall hole 103aa is not limited to the above as long as the wall hole 103aa faces the second opening 30b of the sound hole 30.

The opening area of the opening 103ab of the wall hole 103aa is preferably equal to or larger than the opening area of the second opening 30b of the sound hole 30. When the first braking portion 19 and the second braking portion 106 are not provided in the second opening 30b and the opening 103ab, the equal or more than the above means that the opening area of the opening 103ab itself is the opening of the second opening 30b itself It is to be equal to or greater than the area. When the first braking portion 19 is provided only in the second opening 30b, the equal or more than the above means that the opening area of the opening 103ab itself is equal to or more than the opening area of the first braking portion 19 in the second opening 30b. It is a certain thing. When the second braking portion 106 is provided only in the opening 103ab, the equal or more than the above means that the opening area of the second braking portion 106 in the opening 103ab is equal to or more than the opening area of the second opening 30b itself. It is. When the first braking portion 19 and the second braking portion 106 are provided in the second opening 30b and the opening 103ab, the opening area of the second braking portion 106 in the opening 103ab is the second opening 30b when the first braking portion 19 and the second braking portion 106 are equal to or more than the above. It is equal to or more than the opening area of the first braking portion 19 in the inside.

The cable space 109 is formed between the bottom wall 103 a of the box 103 and the back cover 104. The cable space 109 communicates with the outside of the box 103 and the back cover 104, that is, the outside of the housing of the earphone 100 formed by them. Although not limited to this, in the present embodiment, the cable 105 extends from the outside of the box 103 and the back cover 104 into the cable space 109 along the bottom wall 103 a. Furthermore, in the cable space 109, the cable 105 changes direction and extends in the direction along the sound hole 30, passes through the through hole 103ac formed in the bottom wall 103a, and extends into the speaker back space 110. The cable 105 extends in the direction along the sound hole 30 in the speaker back space 110 and is connected to the speaker 10. In other words, the cable 105 extends from the speaker 10 in the direction along the sound hole 30 in the speaker back space 110.

Next, the configuration of the speaker 10 will be described with reference to FIGS. 3 and 7. FIG. 7 is a schematic cross-sectional side view showing the speaker 10 of FIG. 3 in an enlarged manner. The speaker 10 includes a housing 12 and a diaphragm 11 attached to the housing 12 and emits sound by vibrating the diaphragm 11. In the present embodiment, the outer shape of the speaker 10 is a cylindrical shape, but is not limited thereto, and may be any shape. The speaker 10 includes the diaphragm 11, the housing 12, the stopper 13, the plate 14, the magnet 15, the yoke 16, the spacer 17, the circuit board 18, the first braking portion 19, and the voice coil 20. Equipped with

The circular diaphragm 11 integrally includes a disk-shaped diaphragm body 11 a and an annular or ring-shaped diaphragm edge 11 b surrounding the outer periphery of the diaphragm body 11 a. The diaphragm edge 11 b is flexible, and the diaphragm body 11 a is more rigid than the diaphragm edge 11 b. The outer peripheral edge of the diaphragm edge 11 b is fixed to the housing 12. The diaphragm body 11a is connected to the voice coil 20, and vibrates together with the diaphragm edge 11b while deforming the diaphragm edge 11b by the vibration of the voice coil 20.

The stopper 13, the plate 14, the magnet 15, the yoke 16, the spacer 17, the circuit board 18, the first braking portion 19 and the voice coil 20 are disposed inside the cylindrical casing 12. The stopper 13, the plate 14, the magnet 15, the yoke 16, the spacer 17 and the circuit board 18 are stacked and arranged in this order in the axial center direction of the housing 12 and joined together. In the present embodiment, the axial center of the housing 12 is the axis C, but is not limited thereto.

The circuit board 18 includes an electric circuit and a terminal (not shown), and converts an electric signal of sound supplied from the outside of the speaker 10 through the cable 105 and supplies the electric signal to the voice coil 20. The circuit board 18 has an annular plate shape having a through hole 18 a at the center. The through hole 18 a constitutes a part of the sound hole 30. As shown in FIG. 8, the circuit board 18 is joined to the two core wires 105 a of the cable 105. The two core wires 105a joined to the circuit board 18 are located outside the through holes 18a. FIG. 8 is a view showing the earphone 100 of FIG. 5 upside down. The first braking portion 19 is attached to the circuit board 18 so as to cover the through holes 18 a of the circuit board 18 from the outside. The first braking portion 19 is made of a porous material in at least the region 19a facing the through hole 18a.

The spacers 17 are disposed between the circuit board 18 and the yoke 16 to separate them from one another. The spacer 17 has an annular plate shape having a through hole 17a at the center. The through hole 17 a constitutes a part of the sound hole 30. The spacer 17 may be omitted.

The yoke 16 is made of a magnetic material. The yoke 16 has a cylindrical shape with a bottom, and has an annular plate-like bottom and a cylindrical tube 16b. The bottom has a through hole 16a at the center. The through hole 16 a constitutes a part of the sound hole 30. The yoke 16 is disposed with its bottom portion in contact with the spacer 17. Here, the yoke 16 is an example of a second member.

The magnet 15 is a member having two magnetic poles which are opposite poles. An example of the magnet 15 is a permanent magnet. The magnet 15 has a cylindrical shape having a through hole 15a at the center. The through hole 15 a constitutes a part of the sound hole 30. The magnet 15 is disposed inside the cylindrical portion 16 b of the yoke 16 so as to abut on and coaxial with the yoke 16. A cylindrical air gap is formed between the outer peripheral surface of the magnet 15 and the cylindrical portion 16 b. A second magnetic pole, which is one of the two magnetic poles of the magnet 15, is magnetically coupled to the yoke 16.

The plate 14 is made of a magnetic material. The plate 14 is disposed on the inner side of the cylindrical portion 16 b of the yoke 16 on the opposite side to the bottom of the yoke 16 with respect to the magnet 15. The plate 14 has an annular plate shape having a through hole 14a at the center. The through hole 14 a constitutes a part of the sound hole 30. The plate 14 abuts on and coaxially with the magnet 15. The plate 14 is magnetically coupled to a first pole opposite to the second pole, which is the other of the two poles of the magnet 15. The cylindrical portion 16b of the yoke 16 is disposed outward of the outer peripheral edge 14b of the plate 14, specifically, disposed radially outward of the outer peripheral edge 14b, and is opposed to the outer peripheral edge 14b. A magnetic air gap 22 which is an air gap is formed between the outer peripheral edge 14 b and the inner circumferential surface of the cylindrical portion 16 b. In the magnetic gap 22, a magnetic field is formed between the outer peripheral edge 14b and the cylindrical portion 16b from one to the other. Here, the outer peripheral edge 14b of the plate 14 is an example of the first opposing portion of the first member, and the cylindrical portion 16b of the yoke 16 is an example of the second opposing portion of the second member. The plate 14 as described above, the magnet 15 and the yoke 16 form a magnetic circuit through which magnetic flux circulates.

The stopper 13 is disposed on the plate 14 and the magnet 15 to fix the plate 14 to the magnet 15. The stopper 13 has an annular shape having a through hole 13a at the center. The through hole 13 a constitutes a part of the sound hole 30. The provision of the stopper 13 reduces the volume of the diaphragm back space 31, which is the space between the plate 14 and the diaphragm body 11a. Since the volume of the diaphragm back space 31 relates to the sound quality of the speaker 10, the stopper 13 is also provided to adjust the volume of the diaphragm back space 31.

The voice coil 20 is composed of a cylindrically wound wire. The voice coil 20 is disposed in the magnetic air gap 22 and surrounds the outer peripheral edge 14 b of the plate 14 from the outside. The voice coil 20 is spaced apart and coaxial with the plate 14 and the yoke 16. The voice coil 20 is joined to the diaphragm body 11 a of the diaphragm 11. Further, the voice coil 20 is electrically connected to the circuit board 18. When an electric signal is input to the voice coil 20, the voice coil 20 oscillates in the direction of the axis C by the action of the magnetic field in the magnetic gap 22. As the voice coil 20 vibrates, the diaphragm 11 vibrates, causing a pressure change in the air on the outer surface and the inner surface of the diaphragm 11, thereby generating a sound wave. At this time, the diaphragm 11 emits a sound wave from the outer surface opposite to the diaphragm back space 31.

The stopper 13, the plate 14, the magnet 15, the yoke 16, the spacer 17 and the circuit board 18 assembled together as described above together form a sound hole 30 penetrating them. In other words, the sound hole 30 penetrates the stopper 13, the plate 14, the magnet 15, the yoke 16, the spacer 17 and the circuit board 18. The stopper 13, the plate 14, the magnet 15, the yoke 16, the spacer 17 and the circuit board 18 surround the sound hole 30. Furthermore, the voice coil 20 also surrounds the sound hole 30. The through hole 13 a of the stopper 13 constitutes a first opening 30 a of the sound hole 30, and the through hole 18 a of the circuit board 18 constitutes a second opening 30 b of the sound hole 30.

In addition, the speaker 10 includes the magnetic fluid 21. The magnetic fluid 21 is filled in the magnetic air gap 22 between the voice coil 20 and the outer peripheral edge 14 b of the plate 14. The magnetic fluid 21 is packed around the entire circumference of the outer peripheral edge 14 b and distributed in an annular shape. The magnetic fluid 21 is a fluid containing a material having magnetism. An example of the magnetic fluid 21 is composed of ferromagnetic fine particles (for example, about 10 nm in diameter) such as magnetite and manganese zinc ferrite, a surfactant that covers the surface of the ferromagnetic fine particles, and a base solution such as water and oil. It is a magnetic colloid solution. Although the magnetic fluid 21 is liquid, it has a property of being magnetized and attracted to a magnet. The magnetic fluid 21 may be disposed between the voice coil 20 and the cylindrical portion 16 b of the yoke 16, and between the voice coil 20 and the cylindrical portion 16 b of the yoke 16 and between the voice coil 20 and the plate 14. It may be located at In other words, the magnetic fluid 21 may be disposed between the voice coil 20 and at least one of the cylindrical portion 16 b of the yoke 16 and the outer peripheral edge 14 b of the plate 14.

Such magnetic fluid 21 is held between the voice coil 20 and the outer peripheral edge 14 b of the plate 14 by the magnetic force generated by the magnetic field in the magnetic gap 22 to form a fluid O-ring. Then, the voice coil 20 is supported by the magnetic fluid 21 and the plate 14 by the magnetic force passing through the magnetic fluid 21, whereby the position of the voice coil 20 with respect to the outer peripheral edge 14b is maintained. Moreover, the magnetic fluid 21 seals between the voice coil 20 and the outer peripheral edge 14b by functioning as a fluid O-ring. Therefore, the space on the back side of the diaphragm edge 11 b generating the sound wave and the diaphragm back space 31 are blocked by the magnetic fluid 21. The air in the space on the back side of the diaphragm edge 11 b generating the sound wave is suppressed from leaking to the diaphragm back space 31, whereby the decrease in the sound pressure of the speaker 10 is suppressed.

Moreover, the magnetic fluid 21 is provided with center retention. Therefore, even when the voice coil 20 vibrates with a large amplitude, the magnetic fluid 21 does not contact the diaphragm 11 and the voice coil 20 with the plate 14 and the yoke 16 by the center holding force. It can vibrate stably.

Next, the operation of the earphone 100 according to the embodiment will be described with reference to FIGS. 3 and 7. The circuit board 18 of the speaker 10 converts the electric signal of the sound sent through the cable 105 and outputs the electric signal to the voice coil 20. The voice coil 20 vibrates in the direction of the axis C in response to the received signal to vibrate the diaphragm 11. The diaphragm 11 causes a pressure change in the air on the outer surface and the inner surface, thereby emitting a sound wave toward the sound conduit 102b. The sound wave emitted to the sound conduit 102 b is emitted from the through hole 101 a of the earpiece 101 into the outer ear of the wearer of the earphone 100.

As the diaphragm 11 vibrates in the direction of the axis C, the air in the diaphragm back space 31 and the sound hole 30 vibrates to increase or decrease the pressure. The end of the diaphragm back space 31 is sealed by the magnetic fluid 21. Due to the increase and decrease of the pressure, air reciprocates between the sound hole 30 and the speaker back space 110 through the first braking portion 19. The air flowing out of the sound hole 30 into the speaker back space 110 forms a jet stream directed from the second opening 30 b of the sound hole 30 to the wall hole 103 aa when passing through the plurality of holes of the first braking portion 19. The jet flow smoothly flows toward the wall hole 103aa without interfering with the cable 105, flows into the cable space 109 through the wall hole 103aa, and flows out from the insertion hole 104a of the back cover 104.

When a jet flow is generated in the first braking portion 19, a reaction force in the direction opposite to the flow direction of the jet flow is generated in the first braking portion 19. The parameters of the reaction force are the jet velocity of air, the air density in the sound hole 30, and the opening area of the first braking portion 19. The ejection velocity of the air depends on the compression pressure of the air in the sound hole 30. For example, when the cable 105 is disposed so as to close, cross or be close to the opening of the first braking portion 19, the compression pressure of air, that is, the jet velocity of the air, is the distance between the cable 105 and the first braking portion 19. It changes according to. Thus, the reaction force received by the first braking unit 19 changes. The change in reaction force at the first braking portion 19 affects the vibration of the diaphragm 11 through the air in the diaphragm back space 31 and the sound hole 30. Therefore, the sound pressure generated by the diaphragm 11 may not achieve the desired sound pressure. On the other hand, in the present embodiment, since the cable 105 is disposed as described above with respect to the sound hole 30 and the wall hole 103 aa, the interference between the jet flow and the cable 105 is suppressed. Thus, the sound pressure generated by the diaphragm 11 can achieve a desired sound pressure.

For example, FIG. 9 shows a result of comparison between an example of the earphone 100 according to the embodiment and a comparative example of an earphone having a configuration in which the cable 105 is disposed close to the front of the second opening 30 b of the sound hole 30. It is shown. In addition, FIG. 9 is a figure which shows the sound pressure frequency characteristic in an Example and a comparative example. In FIG. 9, the relationship between the sound pressure and the frequency in the example is shown by a solid line graph, and the relationship between the sound pressure and the frequency in the comparative example is shown by a broken line graph. As shown in FIG. 9, it can be seen that the relationship between the sound pressure and the frequency changes between the example and the comparative example.

In earphones, although the low frequency sound pressure generally increases, the high frequency sound pressure decreases due to the mass of air on the outer surface or front surface of the diaphragm. When a user wearing such an earphone actually listens, the user can hear only the low tone clearly, and the high tone can be heard as a consonant sound of a vocal voice and a muffled sound such as an individual's difference. In particular, in sounds in the frequency band of 1 to 6 kHz, the sound tends to be stagnant. This tendency is determined by the relative sound pressure difference between the low frequency sound pressure and the sound pressure in the above frequency band. Specifically, when the difference is large, the sound stagnation becomes remarkable. For this reason, the sound quality is improved as the sound pressure in the frequency band is closer to the sound pressure at a lower frequency.

As described above, according to the sound output device 1 according to the embodiment, the cable 105 in the speaker back space 110 is the sound hole 30 when viewed from the first opening 30 a to the second opening 30 b of the sound hole 30. Are located outside the area of According to the above aspect, the vibration of the diaphragm 11 of the speaker 10 causes the air in the sound hole 30 to vibrate, and the outflow and the inflow to the speaker back space 110 are repeated. The cable 105 in the speaker back space 110 is disposed outside the area of the sound hole 30, so that the air flowing into the speaker back space 110 is prevented from interfering with the cable 105. Thereby, since the pressure change of the air in the sound hole 30 due to the interference between the outflow air and the cable 105 is suppressed, it is possible to reduce the influence of the vibration of the diaphragm 11 from the pressure change. Therefore, the sound output device 1 enables the improvement of the sound pressure frequency characteristic.

In the sound output device 1 according to the embodiment, a wall portion of the bottom wall 103a forming the speaker back space 110 between the sound hole 30 and the speaker 10 when viewed from the first opening 30a to the second opening 30b of the sound hole 30 The cable 105 in the speaker back space 110 is disposed outside the area of the hole 103aa. According to the above aspect, the air flowing out of the sound hole 30 into the speaker back space 110 smoothly flows out of the speaker back space 110 through the wall hole 103 aa. Therefore, the pressure change of the air in the sound hole 30 due to the interference of the air flowing out to the speaker back space 110 is suppressed.

In the sound output apparatus 1 according to the embodiment, when viewed from the first opening 30a to the second opening 30b of the sound hole 30, one region of the sound hole 30 and the wall hole 103aa is the sound hole 30 and the wall It is included in the other area | region of partial hole 103aa. According to the above aspect, air can efficiently flow from the sound hole 30 to the wall hole 103aa. Therefore, the air flowing out from the sound hole 30 to the speaker back space 110 is prevented from being interfered.

In the sound output device 1 according to the embodiment, the cable 105 is arranged to extend from the speaker 10 in the direction along the sound hole 30 in the speaker back space 110. According to the above aspect, the cable 105 in the speaker back space 110 can be easily disposed outside the area of the sound hole 30. Further, since the area occupied by the cable 105 in the speaker back space 110 can be kept low, the volume of air in the speaker back space 110 can be increased. Thereby, since the pressure fluctuation of the speaker back space 110 at the time of the vibration of the air in the sound hole 30 is suppressed low, the influence of the air in the speaker back space 110 on the air in the sound hole 30 is suppressed.

In the sound output apparatus 1 according to the embodiment, the sound hole 30 is formed to penetrate the plate 14 of the speaker 10, the yoke 16 and the magnet 15. According to the above aspect, since the sound holes 30, the plate 14, the yoke 16, the magnet 15, and the voice coil 20 can be efficiently arranged, the speaker 10 can be miniaturized.

In the sound output device 1 according to the embodiment, the speaker 10 includes the magnetic fluid 21 disposed between the voice coil 20 and at least one of the outer peripheral edge 14 b of the plate 14 and the cylindrical portion 16 b of the yoke 16. According to the above aspect, the magnetic fluid 21 stably holds the vibrating voice coil 20 against at least one of the plate 14 and the yoke 16. Therefore, the sound quality of the speaker 10 can be improved.

In the sound output device 1 according to the embodiment, the sound hole 30 is formed to penetrate the circuit board 18 of the speaker 10. According to the above aspect, since the efficient arrangement of the circuit board 18 in the speaker 10 is possible, the speaker 10 can be miniaturized.

An application example of the sound output device 1 according to the embodiment will be described. As an application example of the sound output apparatus 1 which concerns on embodiment, the hearing aid 200 as shown in FIG. 10 other than the earphone 100 shown in FIG. 1 is mentioned. FIG. 10 is a schematic view showing an example of a hearing aid to which the sound output device 1 according to the embodiment is applied. The hearing aid 200 comprises a receiver 201, a hearing aid body 202 and a lead tube 203. The configuration of the receiver 201 conforms to the configuration of the earpiece 101 of the earphone 100, the port 102, and the sound output device 1.

Moreover, the portable terminal device 300 as shown in FIG. 11 is mentioned as an application example of the sound output apparatus 1 which concerns on embodiment. FIG. 11 is a schematic view showing an example of a portable terminal device to which the sound output device 1 according to the embodiment is applied. The sound output device 1 is applied to the external speaker 301 of the portable terminal device 300 shown in FIG. The portable terminal device 300 is a smart phone in the example shown in FIG. 11, but may be any portable terminal device such as a mobile phone, a tablet terminal, a smart watch or the like.

Further, the sound output device 1 according to the embodiment may be applied to any device provided with a speaker other than the above-described device.

As mentioned above, the above-mentioned embodiment was described as an illustration of art in this indication. However, the technology in the present disclosure is not limited to the above, and is also applicable to embodiments in which changes, substitutions, additions, omissions, and the like are appropriately made. Moreover, it is also possible to combine each component demonstrated by embodiment, and to set it as a new embodiment.

As described above, the technology of the present disclosure is useful for an apparatus provided with a speaker.

1 sound output device 10 speaker 11 diaphragm 14 plate (first member)
14b Outer edge (first opposite part)
15 Magnet 16 Yoke (second member)
16b Tube part (second opposing part)
18 circuit board 19 first braking portion 20 voice coil 21 magnetic fluid 30 sound hole (hole)
30a first opening 30b second opening 31 diaphragm back space 100 earphone 105 cable 108 housing space 109 cable space 110 speaker back space 200 hearing aid 300 portable terminal device

Claims

A speaker having a diaphragm,
A speaker back space located at the back of the speaker opposite to the diaphragm;
A cable electrically connected to the speaker and extending from the inside of the speaker back space to the outside;
The speaker is
A diaphragm back space located behind the diaphragm opposite to the sound radiation direction,
And a hole having a first opening opening to the diaphragm back space and a second opening opening to the speaker back space,
An acoustic output device, wherein the cable in the speaker back space is disposed outside the area of the hole when viewed from the first opening toward the second opening.
It further comprises a wall that forms the speaker back space between the speaker and the speaker,
The wall portion has a wall portion hole that communicates the speaker back space to the outside and is open facing the second opening,
The sound output device according to claim 1, wherein the cable is disposed outside the area of the wall hole when viewed from the first opening toward the second opening.
The area | region of one of the said hole and the said wall part hole is contained in the other area | region of the said hole and the said wall part hole when it sees toward the said 2nd opening from the said 1st opening. Sound output device.
The sound output device according to any one of claims 1 to 3, wherein the cable extends from the speaker in a direction along the hole in the speaker back space.
The speaker is
A magnet surrounding the hole;
A first member surrounding the hole and magnetically coupled to a first pole of the magnet;
A second member surrounding the hole and magnetically coupled to a second magnetic pole of the magnet;
And a voice coil surrounding the hole and connected to the diaphragm.
The voice coil is disposed in a magnetic gap between a first facing portion of the first member and a second facing portion of the second member facing the first facing portion. The sound output device according to any one of the items.
The speaker is
The sound output device according to claim 5, further comprising a magnetic fluid disposed between at least one of the first facing portion and the second facing portion and the voice coil.
The sound output device according to claim 5, wherein the speaker further includes a circuit board surrounding the hole and electrically connected to the voice coil and the cable.
An earphone provided with the sound output device according to any one of claims 1 to 7.
A hearing aid comprising the sound output device according to any one of the preceding claims.
A portable terminal device comprising the sound output device according to any one of claims 1 to 7.